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Reserpine augmentation of desipramine in refractory depression: clinical and neurobiological effects.

Early studies showed dramatic improvement in some depressed patients when a brief course of parenteral reserpine was added to ineffective tricyclic antidepressant (TCA) treatment. We treated eight patients with DSM-III melancholic major depression with desipramine (DMI) greater than or equal to 2.5 mg/kg/day (plasma levels greater than 125 ng/ml) for at least 4 weeks. All patients failed to respond and received reserpine 5 mg IM b.i.d. over 2 days, in seven cases as a placebo-controlled, double-blind trial. One patient had dramatic resolution of depressive and psychotic symptoms within 48 h, but relapsed within 2 weeks; two other patients had transient hypomanic symptoms. Depression ratings did not significantly change for the sample as a whole, but plasma and cerebrospinal fluid (CSF) levels of 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) decreased and CSF levels of homovanillic acid (HVA) and 5-hydroxy-indoleacetic acid (5-HIAA) increased. Despite robust effects on central monoamine metabolism, reserpine augmentation appears insufficiently effective for routine use in managing refractory depression.

Adult↗

Effects of reserpine administration on the fine structure of the rat pars intermedia.

Hormone release from the pars intermedia is under inhibitory control of the hypothalamus. Control may be mediated via dopaminergic fibers which directly contact secretory cells. Administration of reserpine in vivo to adult male rats for four consecutive days results in major alternations in pars intermedia cytology. Cells show expanded areas and whorls of rough endoplasmic reticulum, as well as extensive Golgi zones with numerous dense granules. Some nerve fibers exhibit alterations in vesicle content, while others retain a more normal appearance. Freeze-fracture of glands from reserpine-treated animals provides evidence for exocytosis of granules, although such phenomena are not observed in thin sections. The ultrastructural findings suggest that reserpine alters the content of local inhibitory neurotransmitters in the pars intermedia, leading to unrestrained hormone release, followed by renewed granule synthesis.

Animals↗

Effect of hydrocortisone, reserpine, propranolol and phentolamine on in vivo uptake of exogenous amines by adrenal chromaffin cells.

An autoradiographic study was performed on the effects of hydrocortisone, reserpine, propranolol and phentolamine on the uptake of tritiated amines by adrenal medullary cells of the mouse. Oral feeding of hydrocortisone ahd no significant effect on the normal uptake pattern of dopamine, noradrenaline or adrenaline by medullary cells of different type (A cells or NA cells) or location (marginal or central), although the overall amounts taken up were markedly reduced. Handling the animals led to similar reductions in the uptake of all three amines and was thus clearly shown to be the important factor in this effect. Reserpine reduced the uptake of [3H] noradrenaline to 25% of the control value although the relative distribution remained unchanged. Propranolol and phentolamine had no observed effect on [3H] noradrenaline uptake. These results are discussed in the light of the previously reported action of ACTH in reversing the effects of hypophysectomy on medullary amine uptake (Hirano and Kobayashi 1978), and it is concluded that ACTH must exert this effect directly on the adrenal medulla rather than through the secretion of adrenal corticosteroids. It is also suggested that reserpine acts, as in neurons, by blocking amine uptake into intracellular granules rather than by blocking uptake into the cell itself.

Adrenal Medulla↗

Role of splanchnic nerve on steroid-hormone-induced alteration of adrenomedullary catecholamines in untreated and reserpinized pigeon.

The aim of the present investigation was to ascertain (1) the effect of steroid hormones (corticosterone, dexamethasone, deoxycorticosterone, progesterone, testosterone and oestrogen) on the neural regulation of adrenomedullary catecholamine (CA) content, and (2) the neural modulation of the effect of glucocorticoid hormones (corticosterone and dexamethasone) on reserpine-induced resynthesis of CA. The experiment was conducted on unilaterally splanchnic-denervated pigeons. The findings revealed that 7 consecutive days of steroid treatments (2.5 mg.kg b.w.-1, i.m.) resulted in significant changes of CA content. Interestingly, the changes of epinephrine (E) content differed significantly between the innervated and denervated glands. This clearly indicates that the splanchnic nerve regulates steroid-induced alterations of E content in the pigeon. The results further revealed that the glucocorticoid hormones augmented reserpine-induced resynthesis of CA specifically in the innervated glands. This confirms that the splanchnic nerve is essential for the synergistic action of glucocorticoids and reserpine in accelerating resynthesis of CA.

Adrenal Cortex Hormones↗

The influence of hypothalamically administered reserpine on the sexual behavior of the female cat.

Ovariectomized cats with intracerebral implants of reserpine, a monoamine depletor, were tested for sexual behavior by introducing them to sexually vigorous males and by artificial stimulation. Approximately a third of the animals mated in response to reserpine and another third exhibited some components of sexual behavior. The behavior exhibited by these animals had none of the frenzy of normal estrous behavior. Some components of the normal pattern were missing while all others were curtailed in duration and vigor. These animals responded with normal sexual behavior to intracerebrally and systemically administered estrogen. It is suggested that the unusual sexual behavior in response to reserpine was due to the release of these behavioral patterns from a monoamine system, inhibitory to sexual behavior.

Animals↗

Effect of cyclo(Leu-Gly) on reserpine-induced hypomotility and increases in cortical beta-adrenergic receptors.

Previous studies have indicated that the endogenous peptide, melanotropin release inhibiting factor (MIF) and its analog cyclo(Leu-Gly) ( CLG ) facilitate dopamine (DA) receptor agonist binding and inhibit DA receptor supersensitivity induced by neuroleptics and opiates. The effect of CLG was tested on beta-adrenergic hypersensitivity induced by reserpine to ascertain whether CLG has effects on other neuronal systems besides DA. Administration of reserpine to rats induced hypomotility and enhanced binding of [3H]dihydroalprenolol (DHA) to cortical membranes. Concurrent administration of CLG blocked both the hypomotility and the enhanced [3H]DHA binding to cortical membranes. Lithium has also been shown to prevent reserpine induced hypomotility and increased cortical [3H]DHA binding. These studies suggest that CLG may be producing its effect either like lithium or by an amphetamine like action. If CLG can be shown to have lithium like activity, it could prove to be useful in the treatment of mania.

Animals↗

The effect of reserpine on concurrent repeated administration of d-amphetamine.

The augmentation of the rat stereotypy response with repeated amphetamine doses, put forward as a model of human amphetamine psychosis, was examined during concurrent reserpinization. The effects of reserpinization, amphetamine treatment, and amphetamine dose on four dependent variables representing the time course of stereotypy ratings after a post-treatment amphetamine dose, were tested by three-way MANOVA. An earlier onset of stereotypy , as occurred in nonreserpinized rats, was not detected in reserpinized rats, but an earlier offset of stereotypy with repeated amphetamine occurred in these rats when high amphetamine doses were used.

Animals↗

Serotonergic function in mouse head twitches induced by lithium and reserpine.

We examined the relationship between lithium-induced head twitches and serotonergic neurons. Head twitches were elicited by combined treatment with lithium chloride (2 or 5 mEq/kg x 5, s.c. administered hourly) and rauwolfia alkaloids, i.e., reserpine (5 mg/kg, s.c.), tetrabenazine (20 mg/kg, s.c.), and syrosingopine (10 mg/kg, s.c.). Neither lithium nor the alkaloid alone induced the twitches; nor did combined administration of lithium with methamphetamine or p-chloroamphetamine. The head twitches induced by lithium in combination with reserpine were strongly inhibited by antiserotonin drugs, methysergide and cyproheptadine, and also by a serotonin synthesis inhibitor, p-chlorophenylalanine (PCPA), when administered between lithium and reserpine. When PCPA was administered before lithium for 3 days, the head twitches were potentiated. In addition, the head twitches were potentiated by a serotonin receptor stimulant, 5-methoxy-N,N-dimethyltryptamine. The results imply that lithium can induce head twitches in the presence of rauwolfia alkaloids and may exert its effect in part by acting on the serotonergic neuron system.

Acetylcholine↗

Demonstration of reduced levels of zinc in rat brain after treatment with d-amphetamine, but not after treatment with reserpine.

Histochemical and atomic absorption spectrophotometric methods were used to study the effects of reserpine and d-amphetamine on the neuronal trace metal distribution in various regions of the central nervous system (hippocampus, parietal cortex, cerebellum). Six hours after single d-amphetamine treatment (15 mg/kg i.p.), the neuronal zinc level was significantly decreased in the hippocampus and in the parietal cortex. The intensity of sulphide silver staining was similarly greatly decreased in all layers of the hippocampus and the parietal cortex. Such a change was not observed when d-amphetamine was administered in a lower dose (5 or 10 mg/kg i.p.). Twenty hours after single reserpine treatment (10 mg/kg i.p.), there were no changes in the tissue levels and distribution of zinc, copper, iron and manganese. In animals treated with reserpine on five consecutive days, in a dose of 10 mg/kg/day i.p., the trace metal distribution twenty hours following the final treatment was essentially the same as in the control. The results strongly suggest that zinc does not play a direct role in vivo in the storage and mobilization processes of the catecholamines. A high dose of d-amphetamine, however, has a non-specific, toxic effect that is not interrelated with the catecholaminergic neuronal function; this effect is manifested in a diminished intensity of sulphide silver staining and in a reduction of the tissue zinc level.

Animals↗

Depression of reserpine-induced muscular rigidity in rats after administration of lisuride into the spinal subarachnoid space.

Muscular rigidity was induced by reserpine (10 mg/kg) in rats and the tonic activity of the gastrocnemius muscle was recorded in the electromyogram. Systemic administration of lisuride, an ergoline, resulted in a dose-dependent depression of rigidity. To examine the spinal cord as a site of action for lisuride to depress reserpine-induced rigidity, a method for the chronic catheterization of the lumbar spinal subarachnoid space was used, which allowed the administration of drugs to reserpinized, intact rats without anaesthesia. Lisuride injected into the lumbar spinal subarachnoid space resulted in a longlasting depression of rigidity. These results suggest that the spinal cord is an important site of action of lisuride.

Animals↗

Effects of reserpine and propranolol on anoxia-induced enzyme release from the isolated perfused guinea-pig-heart.

The possibility of a protective effect by reserpine or propranolol on anoxia-induced released of malate and lactate dehydrogenase was investigated in isolated perfused hearts of guinea-pigs. After allowing 30 min of aerobic perfusion for the development of a steady state, the hearts from the nontreated group as well as the reserpine-pretreated or propranolol-treated group were subjected to a prolonged anoxia of 5 hrs. A marked enzyme release which occurred from the anoxic nontreated hearts was significantly inhibited by reserpine or propranolol. These findings suggest that the enzyme release from the anoxic myocardium is partly related to the liberation of endogenous catecholamines.

Animals↗

Prolactin secretion during reserpine and syrosingopine treatment.

In 20 mild hypertensive women, reserpine induced a significant increase in mean plasma PRL, both under basal conditions (from 6.6 +/- 0.9 to 17.9 +/- 2.9 ng/ml), and on repeated determinations during the day. In contrast to reserpine, the administration of syrosingopine, a synthetic compound derived from reserpine, to the same subjects was not followed by a significant change in prolactin level. Beyond their pharmacological interest, these results are of clinical importance when considering that rauwolfia alkaloids are used for long term treatment, and that an increase in PRL levels is important in pathology, both in relation to the function of the hypophyseogonadal axis and in view of its possible facilitation of the growth and development of mammary cancer.

Aged↗

Inhibition of rat mitochondrial functions in vivo by 6-OHDA and reserpine.

Reserpine caused a decrease in the state 3, respiratory control ratio (RCR) and ADP/O ratio in frontal cortex, striatum and liver of rats 1 h after drug administration. State 4 respiratory rate was stimulated in frontal cortex and striatum. In the liver, 6-OHDA decreased the ADP/O ratio when both pyruvate/malate and succinate were used as substrates. Reserpine induced changes in the activities of Na+K(+)-ATPase and Mg(2+)-ATPase in frontal cortex and liver 15 min and 4 h after administration of the drug. In the liver only 6-OHDA caused the depression of Mg(2+)-ATPase activity (P < 0.05). Reserpine altered the levels of K+, Na+ and Ca2+ cations in rat frontal cortex and striatum, while 6-OHDA caused a decrease in the amount of Mg2+ in liver (P < 0.05).

Animals↗

Reserpine- and tetrabenazine-sensitive transport of (3)H-histamine by the neuronal isoform of the vesicular monoamine transporter.

The transport of (3)H-histamine by the endocrine-specific (VMAT1) and neuronal (VMAT2) isoforms of the vesicular monoamine transporter has been evaluated in digitonin-permeabilized fibroblasts transfected with either VMAT1 or VMAT2. Transport of (3)H-histamine by both VMAT1 and VMAT2 was reserpine-sensitive but only transport by VMAT2 was inhibited by tetrabenazine. Maximal equilibrated levels of (3)H-histamine accumulation by VMAT2 (K(m) 300 mu M) were approximately three times greater than that mediated by VMAT1 when using a subsaturating concentration of exogenous (3)H-histamine (50 mu M). The expression of VMAT2 in histaminergic neurons in the rat brain was examined with polyclonal antipeptide antibodies specific for VMAT1 or VMAT2. VMAT2-positive and tyrosine hydroxylase-negative immunoreactive cell bodies were localized to the ventral part of the posterior hypothalamus in the region of the mamillary nuclei. The transport properties of VMAT2 and the distribution of VMAT2 in cell bodies in the tuberomammillary nucleus of the posterior hypothalamus reported here and the apparent absence of VMAT1 and VMAT2 in tissue mast cells support previous findings of reserpine-sensitive and reserpine-resistant pools of histamine in brain and peripheral tissues.

Adrenergic Uptake Inhibitors↗

Therapeutic implications of hypertension-induced glomerular injury. Comparison of enalapril and a combination of hydralazine, reserpine, and hydrochlorothiazide in an experimental model.

Systemic hypertension does not always reflect concomitant glomerular hypertension. At similar levels of systemic hypertension, glomerular injury occurs only in kidneys that lack protective preglomerular vasoconstriction, which results in glomerular hypertension. indeed, glomerular hypertension and glomerular injury do not develop in rats with spontaneous hypertension that have effective preglomerular vasoconstriction. In the experiments reported herein, the normal adaptive response (afferent arteriolar dilation) to a reduction of one and five-sixths of the renal mass in rats with spontaneous hypertension was examined to ascertain whether that response would expose the remaining nephrons to the injurious effects of high perfusion pressure. In addition, the efficacies of two different antihypertensive regimens were compared. Rats with spontaneous hypertension received either no therapy, or a combination of hydralazine, reserpine, and hydrochlorothiazide, or the angiotensin converting enzyme inhibitor enalapril. Three weeks after ablation of one and five-sixths of the renal mass, blood pressure, glomerular filtration rate, urinary protein excretion, and histologic injury scores for mesangial expansion and glomerulosclerosis were determined. Untreated rats with hypertension had severe glomerulosclerosis and mesangial expansion. Both antihypertensive regimens normalized systemic blood pressure and reduced glomerulosclerosis. However, enalapril was more effective than the combination of hydralazine, reserpine, and hydrochlorothiazide in reducing the exaggerated glomerular filtration rate (0.52 +/- 0.40 versus 0.82 +/- 0.10 ml per minute; p less than 0.05), the injury score for mesangial expansion (79 versus 103; p less than 0.05), and the degree of proteinuria (32 +/- 4 versus 42 +/- 3 mg per 24 hours; p less than 0.05). Persistence of hyperfiltration accompanied by increased mesangial expansion, may lead to progression of glomerular damage despite "adequate" control of systemic hypertension, as observed in rats treated with a combination of hydralazine, reserpine, and hydrochlorothiazide.

Animals↗

The chronically reserpinized rat: decreased glycolytic activity in the submandibular gland.

Some of the enzymes and metabolites of the glycolytic pathway of an animal model for cystic fibrosis (the chronically reserpine-treated rat) were investigated. The activities of the enzymes phosphofructokinase (P less than 0.002), enolase (P less than 0.03), pyruvate kinase (P less than 0.005), and lactate dehydrogenase (P less than 0.009) were decreased whereas the activity of glycerol-3-phosphate dehydrogenase was unaffected in the submandibular glands of the treated animals. For metabolites, the reserpine treatment resulted in an increased concentration of glycogen (P less than 0.0002) and phosphoenolpyruvate (P less than 0.001) and a decreased concentration of pyruvate (P less than 0.005) and lactate (P less than 0.002) in the glands. The concentration of glucose and glycerate-2-phosphate was unaffected. The perchloric acid-soluble part of the proteins was also increased (P less than 0.0001) in the submandibular glands of the reserpine-treated animals, as was the activity of ribonuclease. These findings point to a disturbance in the metabolism of glucose and a possible acidosis in the submandibular glands of this animal model for cystic fibrosis.

Animals↗

Behavioural and neurochemical interactions between chronic reserpine and chronic antidepressants. A possible model for the detection of atypical antidepressants.

Chronic treatment with a low dose of reserpine (0.1 mg/kg) caused rats to become hyperactive in the "open field" apparatus. When mianserin (5 mg/kg) or the selective serotonin uptake inhibitor ORG. 6582 (5 mg/kg) was chronically administered in combination with reserpine, the hyperactivity was attenuated. Both antidepressants were found to reverse the reduction in the noradrenaline concentration of the amygdaloid cortex caused by chronic reserpine treatment. It is proposed that changes in the activity of the noradrenergic system in the amygdaloid cortex may be causally related to the changes in activity of the rats in the "open field" apparatus.

Animals↗